Abstract
Summary Habitat conditions, photosynthesis and water relations of three prominent lichen species (Ramalina terebrata, Usnea fasciata, Himantormia lugubris) from the maritime Antarctic were investigated. The ornithocoprophilous R. terebrata had the highest photosynthetic productivity, and water absorption capacity. The two growth forms of U. fasciata although occurring at the same habitat differed widely in their potential net photosynthesis. It is hypothesized that the prostrate growth form is degenerated as a result of competition with bryophytes. Himantormia lugubris had a very low potential photosynthesis. Due to its low productivity it appeared to be inferior competing with U. fasciata on coastal terraces and therefore only exists at the periphery of dense lichen mats. All lichens were capable of absorbing water from a saturated atmosphere. Net photosynthesis was depressed by high thallus water contents only at high temperatures which generally do not occur in their natural environment. Rainwater-soaked thalli remained generally below 8°C under natural conditions.
Published Version
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